Burglar alarm



Jan. 16, 1940. c. M. CHAPMAN 2,187,194

BURGLAR ALARM Filed March 15, 1937 Ead- Patented Jan. 16, 1940 oFFlcE BURGLAR ALARlWI Clifford M. Chapman,

Indianapolis, Ind., as-

signor of one-third to Avada. Storm and twothirds to Russell R. Wilkinson, both of Indianapolis, Ind.

Application March 13,

5 Claims.

This invention relates to an alarm system or apparatus particularly adapted for use as an automatic burglar alarm but also useful as a manually operable alarm for banks and the like. The invention may also be used as a combined re and burglar alarm or as a fire alarm only.

One object of the invention is to provide an alarm which, when operated either automatically or manually, warns the occupants of a building of impending danger or leads an intruder to believe that he is under re from armed guards or other protectors of the premises. To this end there is provided a rearm which is automatically fired repeatedly when the apparatus is operated and which preferably discharges either blank cartridges or gas shells. When the device has been properly placed in a concealed location, the intruder is unable to detect the source of the firing and his natural impulse under the circumstances is to depart as speedily as possible. To add to the effectiveness of the apparatus, an audible alarm device is preferably added together with mechanism operating the alarm device when a predetermined number of shots have been fired or a predetermined length of time has expired.

Other objects and features of the invention will be readily understood from the accompanying drawing and the following description and claims:

Fig. 1 is a plan View of the apparatus assembled in a. suitable container. Fig. 2 is a sectional View on the line 2-2 of Fig. 1. Fig. 3 is a wiring diagram showing the connections within the apparatus and the connections to an external alarm circuit and a remote alarm device, and Figure 4 is a detail fragmentary sectional View through the bracket and showing the manner of connecting the trigger therewith.

In the preferred form of the invention shown by way of illustration in the drawing, there is provided a suitable box or container l having a removable cover ll and within which there are secured a plurality of cells I2 forming a battery for the supply of electric current, a relay i3, a terminal socket It, having external openings for the reception of plugs I5, I5 and la of the usual household type and a base plate Il on which there are mounted the principal mechanical parts of the apparatus.

The base I1 has secured thereto an electric motor I8, having a worm I9 on its rotor shaft meshing with a worm gear 20 which is in turn secured to a horizontal shaft 2l journaled in bearing brackets 22 supported on the plate Il. The shaft 2l has secured to its opposite end a striker 1937, Serial N0. 130,651

in the form of a bar 23 carrying rollers 2li at each end. A repeating revolver 25 has its trigger 26 secured by welding. sweating or otherwise to a stud 21 which is iixedly secured to a bracket 28 carried by the plate I1. In the operation of this part of the apparatus, the energizing of motor I8 rotates the striker in the direction of the arrow in Fig. 2 and repeatedly brings the rollers 24 into contact with the butt of the revolver. Since the trigger 26 is xed, the body of the revolver rotates about the internal pivot of the trigger and the resulting relative motion is the same as when the trigger is manually pressed. The muzzle of the revolver is therefore raised into line with an opening 29 in the casing Il! and is red in that position each time one of the rollers 2li strikes the butt. Preferably, blank cartridges are used, or gas shells may be substituted.

For stopping the motor I8 and initiating the operation of an external alarm device, there is provided a commutator or limit switch consisting of a drum 30 of insulation material carrying a semicircular contact segment 3l on its periphery and a contact plate 32 on o-ne face. The plate 32 is electrically connected to the segment 3l at one end and protrudes at its opposite end, as best seen in Fig. 3, sufciently to engage a contact nger 33 which is normally out of contact with other parts of the commutator. A second contact nger 34 engages the drum 3l) or segment 3|, depending upon the position of the drum. Both fingers are mounted upon an insulation block 35 carried by the base I'I and are insulated from each other.

The drum 3B is freely mounted on a stud 35 which is secured to the upper end of an arm 31 pivotally mounted on a bracket 3B secured to the plate II. A grooved friction pulley 39 of insulation material is secured to the drum 30 and rotates therewith. Said pulley engages a friction pinion 40' carried by the shaft 2l. A' tension spring 4I is secured to the end of stud 36 and to one of the brackets 22 and draws the arm 31 about its pivotal mounting to maintain frictional contact between pulley 39 and pinion 40 for rotating the drum 30 when the motor I8 is in operation.

The relay I3 is of a common form in which an electromagnet 42, when energized, draws a pivotally mounted armature 43 about its pivotal mounting 44 against the action of a tension spring 45. When said electromagnet is energized, the upper end of the armature is pressed against an insulated stop 46 and when said magnet is deenergized the spring draws the armature against a contact member lll.

Referring now to the wiring diagram, one terminal of battery l2 is connected to a main control switch d by conductor 49, which leads through socket lll and plug la. The main switch t3 is preferably a key operated switch and is used to disconnect the apparatus when not in use and to connect it during periods of service. The opposite terminal or" switch B8 is connected to the relay contact lli and to the electromagnet 42 by conductor 5t via plug Ia and socket it. The opposite terminal of electromagnet l2 is connected to the external alarm circuit 5l by conductor 52 via socket lli and plug l5. The external circuit 5l is connected through plug l5, socket lll and conductor 53 to the opposite terminal of the battery l2. The external alarm circuit may be of the usual normally closed form connected to doors, windows or other strategic portions of the premises to be 'protected in such a manner that an intruder' tampering with anv important object therein will open the circuit. As long as the circuit is complete and main switch 18 is closed, the electromagnet l2 is energized and there is no contact between members 33 and fil. Once the external circuit is broken, the electromagnet is deenergized and contact is immediately made between said members.

|fhe armature 43 is connected to Contact plate 32 preferably by a ground connection through plate ll and 3l, and stud 36 which is in electrical Contact with plate 32. This connection is shown diagrammatically in Fig, 3 by the equivalent conductor 5Fl. The contact finger 34 is connected to the motor i8 by conductor 55. The motor is connected to battery l2 by a branch of conductor 53. By means of the wiring just traced, the motor circuit is completed to operate the apparatus when it is set with nger 3ft engaging segment 3l and when contact B3-4'! is closed by thebreaking of the external alarm circuit. When the apparatus is made ready for use, the commutator is referably set manually in the position shown in Fig. 3. The completion of the i3-lll contact, therefore, starts the motor which runs until the commutator has made substantially a half revolution and the El-Sll contact has been broken. During this period, the revolver will be fired repeatedly. Preferably, the time of motor operation is sufficient to permit the revolver to discharge all of its cartridges.

The nger 33 is connected to an external alarm device 55 which may be a bell, buzzer or visual signal located on the protected premises or at a position remote therefrom.. This connection is through conductor 5l via socket ill and plug i6. The alarm device is connected to battery l2 through conductor 5B, a thermostatic timer 5! and a branch of conductor 53 via plug le and socket lil. When the Cil-3d contact is broken, at the end of the motor operation, the 32,-33 contact is closed to complete the following circuit: lil, 19, il?, 5d, 32, 33, 5l, 56, 56, 59, 53, i2. This circuit causes the alarm device to operate and in ordinary circumstances, it will continue to operate until the thermostatic timer 53 opens the circuit at the end of a predetermined length of time. This timer may be of a common form which embodies a snap switch opened by action of a thermostatic element at the end of a predetermined time and thus prevents a second operation of the alarm until the switch has been reset. It may also be of a common intermittent type which provides intermittent operationv of the alarm until its circuit is opened by means of the main switch 48 or otherwise. In either case, the purpose of the timer is to prevent the nuisance of a continuously sounding alarm after the need for the same has passed and beiore the circuits may be manually opened. In installations where a continuous alarm may not be regarded as a nuisance, the timer may be omitted. Obviously, other forms of electrical timers than the thermostatic form may be used-for example, the ratchet type of timer associated with an audible signal described in Weaver Patent No. 1,179,987.

The foregoing specification describes a preferred form of the invention, the details of which may be varied between wide limits without departing from the scope thereof as kdenned by the appended claims. For example, the normally closed external circuit herein described may be replaced by the normally open circuit usually used with manually controlled alarms. To adapt the device for such a circuit, it is only necessary to reverse the positions of the insulated stop 46 and the contact member lll. Thermostatic switches may also be included in the external circuit and the apparatus then becomes a combined iire and burglar alarm. The term firearm as used in the claims is not to be taken as limiting the invention to the use of standard revolvers, rinesl or other arms suitable for other purposes, but is intended to include any form of device capable of exploding a cartridge or gas bomb in a realistic manner.

The invention claimed is:

l. In an alarm apparatus means for mounting a rearm, with its trigger in a xed position, a striker adapted to strike said firearm and to move the same relative to the trigger for discharging the same, and means for actuating said striker.

2. In an alarm apparatus, means for mounting a firearm with its trigger in a fixed position, a rotating striker adapted when rotated to repeatedly strike the firearm to move the same relative to its trigger for repeatedly discharging the same, and means for rotating the striker.

3. In an alarm apparatus, means for mounting a rea-rm with its trigger in a xed position, a rotating striker adapted when rotated to repeatedly strike the firearm to move the same relative to its trigger for repeatedly discharging the same, a motor for rotating said striker, and means for energizing said motor.

4. In an alarm device, a support, a firearm, means on said support to rigidly secure the trigger of the iiring arm to said support, and means for rocking said Jrrearm upon its trigger.

5. In an alarm device, the combination with a repeating rearm to be red upon each retraction of its trigger, of a support, means maintaining said firearm in rocking position upon said support with its trigger affixed thereto, and a motor to rock said firearm.

CLIFFORD Ivi. CHAPMAN. 

